I don't think I've been clear enough, by griefing I simply mean killing somebody who is not hostile/just going about their business. That is acting as an outlaw. It's a game about the wild west. I do not mean following them across the map (in most circumstances) nor across servers. Just a bit of fun killing someone a few times, maybe feuding then leaving it be (if I win).
It's a game, relax. If you don't like other players shooting you then perhaps there are other titles that would suit your sensitivities. Calling people who get shot in a video game where that is both enabled and encouraged is just being overly dramatic. Again, it is a game.
Serious question, when a bear or cougar rips me off my horse and mauls me are they trolling/griefing or is it just part of the game?